Distribution in Texas. Known from western
one-half of state, east to Bosque County.

Habits. The porcupine is adapted
to a variety of habitats. It is largely an inhabitant of
forested areas in the West and prefers rocky areas,
ridges, and slopes. It is less common in flats, valleys,
and gulches. Porcupines wander about a great deal and may
be found irregularly in areas that appear wholly unsuited
to them. In recent years, it has expanded its range into
southern Texas.

They are expert at climbing trees,
although their movements are slow, methodical, and
seemingly awkward. They apparently are aware of their
limitations and they take few chances. Porcupines seem to
be as much at home in the rocks as on the ground or in
trees. The more massive and broken the rocks the better
they serve the animals for the numerous crevices and
caves can be used as den sites and the large boulders as
resting places. Where rocky dens are accessible, they are
visited at intervals by many porcupines from the
surrounding region and are used from year to year. Where
such dens are unavailable a hollow log, a windfall, or an
upturned or loosened tree root system may serve the
purpose.

In winter when snow covers the ground,
porcupines seldom travel far from their dens, especially
in freezing weather. As warm weather approaches, the
amount of travel increases.

Herbaceous ground vegetation makes up
85% of the food of both old and young in summer. In fall
only 27% of their food is herbaceous; 73% is
tree-gathered and includes mistletoe, the inner bark of a
variety of trees, and pine needles. In winter the food is
wholly from trees, and pine needles and inner bark are
consumed at their peak during this season. In spring they
again return to herbaceous ground vegetation which then
makes up nearly 40% of their diet. Throughout the year
the porcupine is more of a browser than a grazer and
subsists in large measure on the inner bark of trees and
shrubs; grass is of no importance at any time of the
year. Porcupines are especially fond of salt and are
easily attracted to it, a fact which is useful in their
control.

Breeding takes place in late summer and
early fall, with the peak of activity in September and
early October. The young, usually one, rarely two, are
born about 7 months later in April and May. The gestation
period is 209-217 days. At birth the young porcupine
weighs about 450 g and is larger than a newborn black
bear. It is covered with a good coat of blackish hair,
the quills are well-developed, the eyes and ears are
functional, and the incisors and some of the cheek teeth
have erupted. It is usually suckled for only a short
period, begins to feed on vegetation shortly after birth,
and soon becomes entirely dependent upon its own
resources. The young porcupines grow slowly as compared
with most rodents, and females do not mature sexually
until their second fall when they weigh about 4 kg.
Porcupines have a relatively long lifespan. One marked
female is known to have lived more than 10 years under
natural conditions.